The CAS Registry Mumber 64445-12-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,4,4,4 and 5 respectively; the second part has 2 digits, 1 and 2 respectively. Calculate Digit Verification of CAS Registry Number 64445-12: (7*6)+(6*4)+(5*4)+(4*4)+(3*5)+(2*1)+(1*2)=121 121 % 10 = 1 So 64445-12-1 is a valid CAS Registry Number.